In 2000, 6.5 kilometers from the Egyptian coast and about ten meters deep, Franck Goddio’s team discovered a city that historians only knew from ancient texts. Its full name: Thonis-Heracleion. It lay sleeping in the Bay of Aboukir, east of Alexandria.
Twenty-five years later, the excavations continue. And the figures circulating online are often outdated or copied from one page to another (the previous version of this article was no exception). So we have reviewed everything based on publications from the European Institute of Underwater Archaeology (IEASM) and the Hilti Foundation, which funds the project.
A clarification before dreaming: you don’t dive at Heracleion as a tourist. We’ll come back to that below, with a realistic lead for those who want to see submerged ruins, like those in our top 7 sunken cities.
When and how was Heracleion discovered?
Heracleion was discovered in 2000 by the European Institute of Underwater Archaeology, led by Franck Goddio, in the western part of the Bay of Aboukir. The site lies about 10 meters deep and 6.5 kilometers from the current shoreline, and the excavations are conducted with the Egyptian Ministry of Tourism and Antiquities.
Before 2000, no trace of the city had been found.
The surveyed area is immense. The IEASM describes a sector of 11 by 15 kilometers, and Franck Goddio speaks of a marine zone of about 110 square kilometers that he could not explore without the support of the Hilti Foundation. Such an area cannot be excavated in one season. Yet, the work progresses. According to the Hilti Foundation, only about 5% of the ancient city has been rediscovered, over an area twice the size of Pompeii.
In short, this is one of the largest underwater archaeology sites in the world, and it is far from finished.
Thonis and Heracleion, one city: how do we know?
Thonis and Heracleion refer to the same city. The Egyptians called it Thonis, the Greeks Heracleion. The decisive proof is a stele commissioned by Pharaoh Nectanebo I, who reigned from 380 to 362 BCE, whose text names the place where it was erected: Thonis. For a long time, two distinct sites were believed to exist.
The stele is barely two meters high (nothing like the “sixteen tons” sometimes mentioned).
Its text is almost identical to that of the Naucratis stele, kept at the Egyptian Museum in Cairo. This decree levies a tax on goods coming from the “sea of the Greeks,” for the benefit of the temple of the goddess Neith at Sais. Thus, Thonis served as the gateway. According to the Hilti Foundation, it was the mandatory port of arrival for all ships coming from the Greek world. This explains its wealth. Herodotus, a Greek historian of the 5th century BCE, already recounts that a great temple had been built where the hero Heracles supposedly first set foot in Egypt.
This Heracles gave his name to the city, amid a pantheon where the gods of the sea and river held great importance.
What has been found at the bottom of the Bay of Aboukir?
The excavations have yielded colossal red granite statues, the great temple of Amon-Gereb, 125 shipwrecks dated from the 6th to the 2nd century BCE, and more than 700 ancient anchors, according to the IEASM. These figures far exceed those still read elsewhere.
The statues are striking first. The god Hapy, who embodies the Nile flood, measures 5.4 meters. A Ptolemaic king and queen, each about five meters tall, now welcome visitors in the entrance hall of the Grand Egyptian Museum in Giza, according to the Hilti Foundation in 2023. The queen alone weighs four tons. But the most telling details lie in the small objects.
In 2023, the team recovered from the treasure of the temple of Amon ritual instruments in silver, gold jewelry, and fragile alabaster perfume vases, which remained intact despite the violence of the catastrophe.
To the east of the temple, a Greek sanctuary dedicated to Aphrodite yielded bronzes and imported ceramics. Greeks and Egyptians prayed just a few steps from each other. In 2021, divers uncovered a fast galley from the Ptolemaic era, dated to the 2nd century BCE and over 25 meters long. It sank beneath the blocks of the temple of Amon. It rested under nearly five meters of hard clay, not “intact at six meters deep” as often written. A Greek funerary area from the early 4th century BCE also appeared that same year.
Why Did Heracleion Disappear?
Heracleion sank in stages. According to the Hilti Foundation, several earthquakes and tsunamis caused the liquefaction of the Nile Delta soil, and the city was eventually completely submerged in the 8th century AD. Before the founding of Alexandria in 331 BC, it was the largest port in Egypt.
Liquefaction is easy to understand. Water-saturated soil, shaken by an earthquake, loses its strength and temporarily behaves like a liquid. Heavy buildings sink. The city was located at water level, on the low and unstable lands of the delta, with a massive temple and quays loaded with stone that weighed heavily on this ground. The 2021 galley illustrates this well, as it sank when blocks from the Temple of Amun collapsed on it during an earthquake.
The catastrophe was therefore not a single day of the end of the world.
This slow demise also explains the preservation of objects. Once covered with clay and sand, they were protected from air and looters for centuries. This is a boon for archaeologists.
Can You Dive at Heracleion?
No. Heracleion is an excavation site, not a tourist diving spot: only teams from IEASM, working with the Egyptian Ministry of Tourism and Antiquities, dive there. If an offer promises otherwise, ask in writing what official authorization it holds for this specific site. You will quickly know what to expect.
The real alternative starts at the museum. The Ptolemaic king and queen await you in the lobby of the Grand Egyptian Museum near Cairo. For diving, Alexandria remains the closest option. Local centers have offered dives for years around the Qaitbay Citadel and the Eastern Harbor, where ancient blocks rest, but the only dated article found is from 2017. The current status of this offer is therefore impossible to determine from here.
Before booking, ask about the depth, current visibility, supervision, and the planned route if the sea is rough.
For ruins open to the public, look more towards Italy. The sunken Roman city of Baia can be dived with authorized centers. And if Egypt remains your goal, our diving holidays in Egypt detail the Red Sea, much easier to organize. The detour via Alexandria will cost you at least an extra day, for a dive that may be canceled.
FAQ
When Was the City of Heracleion Discovered?
It was discovered in 2000 by the European Institute for Underwater Archaeology, led by Franck Goddio, in the Bay of Aboukir. The site lies about 10 meters deep and 6.5 kilometers from the current coast.
Why Is It Called Thonis-Heracleion?
Because Thonis and Heracleion are the same city. Thonis was its Egyptian name, Heracleion its Greek name. A stele of Pharaoh Nectanebo I found on site names the site Thonis.
Can You Dive on the Heracleion Site?
No, the site is reserved for authorized excavation teams. There is no tourist diving at Heracleion. To see submerged ruins, you must target sites open to the public, such as Baia in Italy.
Where Can You See Objects Found at Heracleion?
The colossal statues of a Ptolemaic king and queen are exhibited in the entrance hall of the Grand Egyptian Museum in Giza. Other pieces have circulated in major international exhibitions. Check with museums before you go.
How Many Shipwrecks Have Been Found at Heracleion?
IEASM lists 125 shipwrecks dated from the 6th to the 2nd century BC and more than 700 ancient anchors. Excavations continue, and these numbers may still change.
Sources
- Thonis-Heracleion (Franck Goddio / European Institute for Underwater Archaeology, accessed in 2026)
- New Archaeological Treasures Found in the Bay of Aboukir (Hilti Foundation, 2021)
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